In October 2025, the Defence Research and Development Organisation, in collaboration with the Integrated Defence Staff and the three Services, released the Indian Radio Software Architecture (IRSA) Standard 1.0. The IRSA is India’s first national specification for software-defined radio (SDR) systems. The standard defines a common software framework for military radios through standardised interfaces, application programming interfaces (APIs), execution environments and mechanisms that allow communication waveforms to operate across different radio platforms. This development represents an important step in India’s defence technology ecosystem.

The SDRs perform core radio functions such as modulation, networking and signal processing. In an SDR, compared to traditional radios, these functions are implemented through software rather than fixed hardware. Therefore, SDR sovereignty becomes central to contemporary military communications.

However, SDR technology introduces a structural challenge. Radios produced by different manufacturers often rely on proprietary software architectures, making it difficult to share communication protocols or ‘waveforms’ across multiple platforms. This fragmentation undermines interoperability within the armed forces and may complicate joint operations. The IRSA attempts to address this problem by creating a standardised software architecture that makes waveforms portable across different SDR hardware platforms.

Broadly speaking, this initiative reflects a shift in India’s defence technology ecosystem from focusing solely on individual platforms, to building digital architectures and software ecosystems that support long-term operational capability.

Software-Defined Radios and the Interoperability Challenge

The growing reliance on digital communications has transformed the role of military radios in modern warfare.  Traditional military radios were largely hardware-bound. Once deployed, their communication protocols and signal processing characteristics were difficult to modify without replacing or redesigning the hardware itself. Software-defined radios fundamentally change this model because many of these functions are implemented through software waveforms rather than fixed circuitry.[i]

Unlike conventional radios that work around fixed hardware configurations, software-defined radio systems implement multiple communication functions through software. Their core features, such as modulation schemes, encryption mechanisms, networking protocols and anti-jamming techniques, are encapsulated in a digital format—also known as waveforms.[ii] This allows a single radio platform to support multiple communication modes simply by loading different waveform software.

In practical terms, this means a single radio can support multiple communication roles simultaneously. For example, it can function as a tactical voice network for ground units, a data link for sensor feeds, a secure command network, or a relay link for unmanned systems. Each of these can operate as separate waveform modules within the same radio platform. The same platform can also utilise high-bandwidth data links, low-probability-of-intercept tactical links and long-range communication channels. Traditionally, different radios or specialised communication systems were needed to support each of these roles.

This is one of the key technological foundations of network-centric warfare, where platforms and units share information across interconnected digital networks.[iii] This flexibility has made SDRs a key enabler of modern command, control and information-sharing systems associated with network-centric warfare. It supports seamless data exchange among sensors, combat platforms and command centres, which is essential for maintaining situational awareness and enabling coordinated operations across domains.[iv]

However, the shift towards software-based communication architectures has also created interoperability challenges. If the military or any armed force........

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